Mounting construction for diaphragm in forming press



Jan. 29, 1963 c. L. MITCHELL MOUNTING CONSTRUCTION FOR OIAPHRAGN 1N FORMING PRESS Filed July '7, 1960 2 Sheets-Sheet l INVENTOR. CHHLES L. MITCHELL TTORNE'YS Jan. 29, 1963 MOUNTING CONSTRUCTION Filed July 7, 1960 C. L. MITCHELL FOR DIAPHRAGM IN FORMING PRESS 2 Sheets-Sheet 2 l'lllll/l/l MWA .......II'll-...l'l'l Fi g.2

'lllllllllllllllll INVENTOR. CHRL ES L. MITCHELL TTORNEYS ilnited 3,675,485 yatentecl Jan. 29, 1963 ice 3,675,485 MUNTING CNSTRUCHN FUR DIAPHRAGM 1N FRMING PRESS Charles L. Mitcheil, Cincinnati, Ohio, assigner to The Cincinnati Milling Machine Company, Cincinnati,

hio, a corporation of Ohio Fiied .hilly 7, 1966, Ser. No. 41,363 6 Claims. (Cl. 113-44) The present invention relates to a forming press of the type in which pressure is applied to the workpiece through a tlexible diaphragm for forming, and, more particularly, to mounting structure for the diaphragm.

In a forming press having a diaphragm constituting a liexible die element thereof it is necessary that the diaphragm contain the pressure medium, such as the hydraulic fluid, which, when under pressure, applies the forming force through the diaphragm to the workpiece. In a typical press construction the pressure lluid is received in a chamber and the diaphragm is snugly received in one end of the chamber in sealing relation therewith. Since the diaphragm is liexible and its the chamber snu-gly, replacement of the diaphragm can be time consuming, and insertion of the new diaphragm, in proper alignment without cooking, diiiicult. In the present invention there is provided a rigid casing in which the diaphragm can be quickly mounted, without cooking, outside the machine, and the rigid assembly can be readily mounted in the press. It is therefore one object of the present invention to provide a construction which permits quick and easy insertion of the diaphragm in the press. It is another object of the present invention to provide mounting structure with which the diaphragm can be preassembled outside the forming press to produce a rigid assembly which can be installed in the press more readily than the flexible diaphragm alone.

While it is important that the diaphragm be securely held in the chamber containing the pressure fluid, it is desirable that creep of the diaphragm be possible during forming to minimize the possibility of rupture when, for example, a deep workpiece is being formed. To accomplish this there is provided a mounting frame which grips the diaphragm to hold the diaphragm securely when the press is open but which oats with the diaphragm in the chamber when the press is closed for forming. It is therefore another object of the present invention to provide an improved mounting structure to hold the diaphragm securely within the press in sealing relation therewith. It is still another o-bjiect of the present invention to provide a mounting structure permitting creep of the diaphragm during forming to minimize the possibility of rupture thereof.

Other objects and advantages of the present invention should be readily apparent by reference to the following specication, considered in 4conjunction with the accompanying drawings forming a part thereof, and it is to be understood that any modifications may be made in the exact structural details there shown and described, within the scope of the appended claims, without departing from or exceeding the spirit of the invention.

In the drawings:

FIG. 1 is a cross sectional View of the diaphragm mounted in the head of the press, showing the position therein when the press is open;

FIG. 2 is a fragmentary cross sectional view similar to FIG. l but showing the position of the diaphragm when the press is closed; and

FIG. 3 is a view taken on the line 3-3 of HG. l. 'Ihe diaphragm and mounting structure of the present invention is particularly suited for use in a forming press of the type shown in U.S. Patent 2,766,711 and U.S. Patent 2,878,767. ln the illustrative embodiment of the invention shown and described herein the press has a head 10 with a pressure chamber 11 therein, the lower portion of the wall 10a thereof being cylindrical in conformation with a circular opening at its lower end. The machine has an annular nest, or bed member, 12 adapted to support a workpiece blank 13. The head 1t? and bed member 12 are relatively movable so that they can be separated, or opened, as shown in FIG. l, for removal of a finished workpiece when separated far enough for clearance of the formed piece, and for insertion of a workpiece blank 13. rThe pressure chamber has an opening, not shown, to receive hydraulic lluid which is retained therein by a diaphragm 141. When the press is closed, as shown in FIG. 2, the diaphragm engages the workpiece blank 13 on the bed member 12. During forming the hydraulic fluid in the pressure chamber is subjected to a high pressure and a male die, or punch, 15 is raised from within the bed member 12, the high pressure fluid in the chamber behind the diaphragm pressing the blank 13 through the flexible diaphragm 14 against the raised punch to form the workpiece to the shape of the punch. After forming, the pressure in the chamber is relieved, and the press is opened to remove the nished workpiece.

In a typical construction heretofore the diaphragm had an upturned flange which was received directly in the lower end of the pressure chamber. Sin-ce it is necessary that the diaphragm contain the fluid within the chamber even when the fluid is not under pressure, a relatively tight initial sealing fit between the diaphragm and the walls of the chamber was required. It is diicult, in molding the diaphragm (which may, for example, be made of rubber), to hold the outer diameter thereof to close tolerances. lf the lit between the diaphragm and the chamber were too tight, diliiculty could be experienced in inserting the diaphragm in the chamber, particularly since the diaphragm is llexible. It the lit were too loose, an adequate seal would not be effected between the diaphragm and the chamber.

To overcome these diiculties there is provided in the present invention a casing, or sleeve, 16 in which the diaphragm 14 can be installed outside the machine. The diaphragm includes a wear pad 14a adapted to engage the workpiece, and an upturned flange 1411 of annular cross section. A mounting frame, or ring 17, has an upper portion 1717 and a depending portion 18. The depending portion 18 is received inside the upper portion of the diaphragm llange and has a tapering outer surface 13a adapted to engage a mating inner surface 14C on the upper portion of the flange 14 to urge that portion of the flange outwardly. The depending portion 18 of the mounting ring also has an external circular groove 18]: which, when the mounting ring is pressed, or wedged, into the upper portion ot the diaphragm tlange, receives an inner bead 14d of the flange in gripping relation. The upper portion 1717 of the mounting ring 17 is above the diaphragm and, although not extending beyond the outer periphery of the sleeve 16, has a shoulder 17a adapted to engage the upper edge of the sleeve 16 to limit downward movement of the ring 17 relative to the sleeve 16. The dimension of the outer diameter of the diaphragm is not critical since even if this dimension is such that the diaphragm, when relaxed, will readily slip into the sleeve without effecting a sealing relation therewith, the mounting ring 17, which grips and spreads the upper portion of the diaphragm flange, will preload the upper portion of the diaphragm flange into sealing relation with the sleeve 16. Thus the unit, or assembly, comprising sleeve 16, diayand the outer diameter of the sleeve 16 which may, for

example, be made of steel, can be more easily held to tolerances permitting a close, but slidable, fit with the pressure chamber than the outer diameter of the molded diaphragm. The head has an annular groove 10b in the wall 10a of the ypressure chamber, and a flexible O-ring 10c is received therein which, with the sleeve, provides a seal which prevents the escape of fluid between the wall of the pressure chamber and the sleeve. The sleeve 16, even if relatively thin, deines a rigid casing, containing the diaphragm therein, which can be more easily inserted in the pressure chamber than the flexible diaphragm alone.

The sleeve 16 has a lower flange 16a and the sleeve is secured in the pressure chamber with the ange 16a clamped against the lower surface of the head 1d. This is accomplished by two arcuate clamp members 19 and 2d,

.each pivotally connected at one end to the head, as by bolt 21 shown in FIG. 3. Each clamp member is swingable to aposition concentric with the pressure chamber opening and, in Vthisposition, the sleeve flange 16a seats on upper shoulders 19a and 2da of the Vrespective clamp members. When the clamp members are in this inner, closed position the end of each clamp member opposite its pivot connection is secured by bolt 22. When bolts 22 are loosened the clamp members can swing away from the pressure chamber opening to permit insertion-and removal of the sleeve.

`An annular retainer ring 23 is slidably received in the sleeve 16 below the diaphragm and has an upper surface "23a adapted to engage in mating relation with the peripheral annular surface portion 14e on the underside of the diaphragm. The ring 23 has a depending flange 2317 and the clamp members 19 and 2t) have lower shoulders 19h and 24lb which, when the clamp members are closed, are adapted to .engage the lower surface of the iiange 23h to limit downward movement of the ring 23 relative to the sleeve. When the press is open, as shown in PIG. 1, the mounting ring 17 and retainer ring 23 drop to their lowermost limit of movement relative to the sleeve and both jointlysupport the diaphragm within the sleeve 16. The retainer ring 23 has a shoulder 23C which defines an abutment surface seating on the bed member 12 when Vthe press is closed, as shown in FIG. 2, holding the retainer ring above its lower position relative to the sleeve, thereby lifting the diaphragm within the sleeve and raising mounting ring 17 oft the sleeve. With this construction, the diaphragm flange within the sleeve is not restrained by the mounting ring when the press is closed. Thus any tendency of the diaphragm ange to creep within the .sleeve as a result of a deep draw is .not impeded by the mounting ring and the possibility of diaphragm rupture is lessened. The mounting ring, since it grips the upper Yportion of the diaphragm flange and continuously urges it outwardly, continuously maintains the fluid seal between the diaphragm and the sleeve whether the press is open or closed.

To insert the diaphragm in the press the bed member k12 .and head 10 are separated and the retainer ring 23 is placed over the bed member 12. The preassembled rigid unit comprising the sleeve 16, the diaphragm 14 and the mounting ring 17 is placed on the retainer ring. Preferably, kthe inner wall of the flange 23h deiin'es a fit with thetbed member 12 which locates the ring 23, and hence the sleeve 16,inproper. position for insertion of the upper .edge of the sleeve, which is beveled at lob, iinto the 'lower opening of the pressure chamber. The press is 'then closed and when the sleeve flange 16a abuts the head, the clamp members 19 and 2t) are swung closed and 'the bolts 22 tightened.

What is claimed is:

1. In combination with a head member of a forming press having means defining a fluid pressure chamber open at its lower end, a rigid casing slidably received in the lower end of the pressure chamber in sealing relation therewith, means to secure the casing in the pressure chamber, a flexible diaphragm having an upstanding flange slidably received in the casing to close the lower end thereof, and a mounting frame having an upper portion above the diaphragm flange and having a depending portion within the flange, said depending portion wedged into the flange to hold the diaphragm and spread said flange into sealing relation with the casing, said upper portion of the mounting frame having means to engage the casing to limit downward movement of the mounting frame and diaphragm within the casing.

2. In combination with a head member of a forming press having means defining a fluid pressure chamber open at its lower end, a rigid sleeve slidably received in the lower end of the pressure chamber, means providing a seal between the walls of the pressure chamber and the sleeve, means to secure thesleeve in the pressure-chamber, a flexible diaphragm slidably received in the sleeve to close the lower end of the sleeve, said diaphragm having an upstariding flange with an inwardly extending bead Within the sleeve, a mounting ring having an upper portion above the diaphragm'flange and having a depending portion received within said ange, lsaid depending portion engaged with the flange to spread the flange into sealing relation with the sleeve, said depending portion having a groove to receive the ange bead in gripping relation, the upper portion of the mounting ring having a shoulder adapted for engagement by the sleeve to limit downward movement of the mounting-ring and diaphragm within the sleeve.

3. In a forming press the combination comprising a head defining a uid pressure chamber open at its lower end and a bed member below the head, the head and the bed member relatively movable to open from .a closed forming position, a rigid sleeve slidably received in the lower endv of the pressure chamber, a flexible member to provide a seal between the walls of the chamber and the sleeve, a clamp on the head to secure the sleeve in the pressure chamber, a flexible diaphragm slidably received in the sleeve to close the lower end of the sleeve, said diaphragm having an upstanding flange with an inwardly extending bead within the sleeve, a mounting ring having an upper portion above the diaphragm flange and having a depending portion received within said flange, said depending portion having a tapering outer surface engaged with the flange to spread the ange into sealing relation with the sleeve, said depending portion having a groove to receive the ilange bead in gripping relation, the upper portion ofthe mounting ring having a shoulder above the upper edge of the sleeve for engagement by the sleeve to limit downward movement of the mounting ring within the sleeve, a retainer ring slidably received in the sleeve below the diaphragm and engaged therewith, the retainer ring having an abutment surface adapted to engage the bed member when the head and the bed member are in the forming position, the retainer ring supporting the diaphragm in a raised position within the sleeve when the head and bed member are in the forming position, and means to limit the downward movement of the retainer ring when the head and bed member are separated whereby the mounting ring and retainer ring together support the diaphragm in the sleeve when the head and bed member are separated.

4. In a forming press the combination comprising a head defining a iluid pressure chamber open at its lower end and a bed member below the head, the bed member and head relatively movable to open from a closed forming position, a rigid sleeve slidably received in the lower end of the pressure chamber, an annular flexible member mounted in sealing relation with the sleeve and lthe walls of the pressure chamber, a flexible diaphragm slidably received in the sleeve to close the lower end thereof, said diaphragm having an upstanding ange with a tapering inner surface and an inner bead within the sleeve, a mounting ring having an upper portion above the diaphragm ange and having a depending portion received within said flange, said depending portion having a tapering outer surface engaged with the tapering inner surface of the llange to spread the flange into sealing relation with the sleeve, said depending portion having an external groove to receive the flange bead in gripping relation, the upper portion of the mounting ring having a shoulder above the upper edge of the sleeve for engagement by the sleeve to limit downward movement of the mounting ring within the sleeve, a clamping member pivotally connected at one end to the head adjacent the opening therein, said clamping member having means to hold the sleeve in the head when the clamping member is closed and having an inner shoulder swingable to a position concentric with the opening When the clamping member is closed, a retainer ring slidably received in the sleeve below the diaphragm and engaged therewith, the retainer ring seating on the inner shoulder of the clamping member when the clamping member is closed and the head and bed member are open to limit downward movement of the retainer ring Within the sleeve, the retainer ring and the mounting ring together supporting the diaphragm within the sleeve when the retainer ring and mounting ring are at their lower limit within the sleeve, the retainer ring having an abutment surface adapted to engage the bed member when the head and bed member are in the forming position to hold the retainer ring above its lower limit within the sleeve, the retainer ring thereby holding the diaphragm in a position within the sleeve to hold the shoulder of the mounting ring olf the upper edge of the sleeve.

5. A fluid pressure chamber exible die assembly for 6 a forming press comprising in combination a rigid casing open at both ends and formed to fit within the fluid pressure chamber, a flexible diaphragm received in the casing to close one end thereof, said diaphragm having an upstanding ange within the casing and terminating therein, and a mounting frame of a size to lit within the fluid pressure chamber having one portion wedged inside the flange in gripping relation therewith to spread said flange into sealing relation with the casing, said mounting frame having another portion connected to said one portion and engaged with the casing beyond the ilange to hold the diaphragm in the casing.

6. A fluid pressure chamber flexible die assembly for a forming press comprising in combination a rigid sleeve of a diameter to be slidably received in the uid pressure chamber in sealing relation therewith, a exible diaphragm received in the sleeve to close one end thereof and having an upstanding flange within the sleeve, said flange terminating inside the sleeve and having an internal bead, a mounting ring having a rst portion received within the flange, said rst portion having a tapering outer surface engaged With the flange to hold the ange in sealing relation with the sleeve and having an external groove to receive the internal bead of the flange, said mounting ring having a second portion connected to said rst portion and extending beyond said ange, said second p0rtion having a shoulder of a diameter to fit within said fluid pressure chamber and to engage the end of the sleeve opposite said one end.

References Cited in the le of this patent UNITED STATES PATENTS 2,878,767 Paulton Mar. 24, 1959 2,908,238 Bringewald Oct. 13, 1959 2,966,873 Hoifman et al. Jan. 3, 1961 

5. A FLUID PRESSURE CHAMBER FLEXIBLE DIE ASSEMBLY FOR A FORMING PRESS COMPRISING IN COMBINATION A RIGID CASING OPEN AT BOTH ENDS AND FOEMED TO FIT WITHIN THE FLUID PRESSURE CHAMBER, A FLEXIBLE DIAPHRAGM RECEIVED IN THE CASING TO CLOSE ONE END THEREOF, SAID DIAPHRAGM HAVING AN UPSTANDING FLANGE WITHIN THE CASING AND TERMINATING THEREIN, AND A MOUNTING FRAME OF A SIZE TO FIT WITHIN THE FLUID PRESSURE CHAMBER HAVING ONE PORTION WEDGED INSIDE THE FLANGE IN GRIPPING RELATION THEREWITH TO SPREAD SAID FLANGE INTO SEALING RELATION WITH THE CASING, SAID MOUNTING FRAME HAVING ANOTHER PORTION CONNECTED TO SAID ONE PORTION AND ENGAGED WITH THE CASING BEYOND THE FLANGE TO HOLD THE DIAPHRAGM IN THE CASING. 